Electrical fire alarm



Patented Oct. 20, 1936 PATENT OFFICE ELECTRICAL FIRE ALARM Ronald Purvis Jameson, Christchurch, New Zealand Application March 31, 1933, Serial No. 663,846 In New Zealand April 11, 1932 5 Claims. (01. 1774455) This invention relates to fire alarm systems.

The object of the present invention is to give an indication at an indicator board on what floor or part of a building a fire commenced.

According to the present invention, when a fire occurs, a circuit breaking device is caused tooperate to open or close an electrical shutter circuit which, in turn, will instantly drop a shutter indicating the locality or floor on which the fire has first broken out, means being provided for preventing the other indicating shutters from falling as far as the first shutter, thereby avoiding the possibility of confusing the brigade or other persons concerned as to the original location of the fire in the building.

The invention will be described with the aid of the accompanying drawings, wherein:--

Figure 1 is a side elevation of the device.

Figure 2 is an end elevation thereof.

Figure 3 is a cross section including a bell contact.

Figure 4 is a diagram of a shutter circuit.

Figure 5 shows the circuit breaking device on each floor.

Figure 6 shows the diiferent positions of the shutter blade.

Referring to the drawings, a horizontal rod I8 is mounted in arms IQ fixed upon another rod 20 mounted in bearings 2| (see Figure 1) in the end uprights of a frame A counter-weighted lever 2| fixed on the rods l8 and 20 has an extension 22 so that it can be raised manually.

A rod 44 is pivotally connected by links 45 to the rod l8 and is guided in slots 46 (see Figure 2) in the uprights of the frame Shutter blades 4| pivotally mounted and normally held in their unexposed position by the electromagnet 9, 9 fall, when the current through the line is broken and actuate the rod I3 to lower link 45. The

lever 2 I is such that when a blade 4| strikes the rod |8 it will be carried from the position in full lines Figure 6 to the position in dotted lines and carry down the rod 44. The weight of the blade 4| is suflicient to overcome the eifect of the counter-balanced lever 2 l The coil 9 shown in the diagram in Figure 4 represents a drop shutter coil Wired to a battery 8, and to a circuit breaker 41, and as shown in Figure 5, one of these circuit breakers is placed in each floor of the building and wired tothe coil of a separate drop shutter, so that there would be a separate drop shutter for each floor, the blades of which would be numbered so as to indicate the floor they represent. These shutters are the usual type, one of which is illustrated in Figure 6, and consists of the usual coil 9, core 9 shutter blade 4| with the iron armature 4| thereon.

' -In Figure 3,-one of the arms IS on the rod 2|], is shown with an insulated tip l9 adapted to engage two spring contacts 34, with spring contact 35, both attached to an insulated block 36 on a plate 31 attached to the frame, thereby closing a bell circuit. When the rod l8 drops to the position in dotted lines, these contacts are closed by the insulated tip I9 and complete a circuit through a bell. Thus, a local warning is obtained immediately the first shutter falls.

When a fire breaks out, for example on floor referenced A, Figure 5, and the circuit breaking device 41, which may be a thermostat or a mechanical breaker operated by the flow of water in a sprinkler system of any known type, breaks the shutter circuit which is a normally closed circuit, the current fails through the coil 9 (see Figure 6) and the blade 4| will fall and strike the rod l8 and cause it, together with the lever 2| to assume the position shown in dotted lines in Figure 2, and in Figure 6. The blade 4| will then lie in a nearly horizontal position with its number exposed to a viewing opening 50 (see Figure 6). After this, should another shutter (say 4l wired to another circuit breaker 41 on floor B) fall it can only fall as far as the rod 44 and its number will be visible through the opening 50 (see Figure 6).

During the interval between the falling of the first shutter, and before the matter can be attended to, additional shutters, other than the one first operated and indicating the floor or locality in which the fire started, may be caused to fall by the spread of heat, but since they do not completely fall, confusion as to the original seat of the fire is avoided, other fioors afterwards affected are indicated through the slot 50 This indicator system is very useful with sprinkler devices.

What I claim is:-

1. In a fire alarm device, a frame, a horizontal rod mounted in said frame, arms mounted on said rod and a second rod mounted on said arms, a counterweighted lever rotatably mounted on said first named rod, said second named rod having a bearing in said counterweighted lever, a projection on said frame having vertical slots therein and a third horizontal rod movably supported in said slots, links connecting said last named rod to said second rod for movement therewith, the counterweighted lever being Weighted on the opposite side of said first named rod and normally holding said links in their upper position indicating shutters, means for pivotally supporting said indicating shutters so located that the shutters will fall upon the second rod in approaching a horizontal position, separate electromagnetic means for holding each of said shutters in an upwardly inclined position, the construction and arrangement being such that on the release of one shutter by said electro-magnetic holding means said shutter upon striking said second rod will force it downward thereby lowering said third rod into the path of other shutters and preventing their falling to the same extent.

2. The device as claimed in claim 1 in which there is a separate control circuit to each of several different localities of the building in which the device is located and a temperature responsive circuit breaking device in said circuit located in each of said localities, said circuits controlling the individual shutters.

3. In a fire alarm device for a building, a plurality of pivoted signalling shutters one for each of several parts of the building, separate electro-magnetic means for holding said shutters in non-signalling position, a circuit breaking device for each said electro-magnetic means, located in each of said several parts of the build ing said shutters being arranged to fall into signalling positions on release of their electromagnetic holding means, a stop rod and means for moving said stop rod into the path of the remaining shutters when one shutter has fallen to full signalling position whereby said stop rod holds any of the remaining shutters which fall, in an intermediate signalling position.

4. The device as claimed in claim 3 in which the means for moving said stop rod comprises a movable horizontal rod in the path of the first shutter to fall and links connecting said horizontal rod to the stop rod.

5. The device as claimed in claim 3 having a cover for said shutters with two apertures therein, through one of which only a first fallen shutter may be seen and through the other of which only the shutters in intermediate position may be seen.

R. P. JAMESON. 

